This invention relates in general to combination locks and in particular to an improved fence lever control device for normally maintaining the fence lever out of engagement with the cam wheel of the lock which is utilized for operating the lever to move the lock bolt between lock open and lock closed positions.
It is common in combination locks, such as that disclosed in the U.S. Pat. No. 4,142,388, for the nose portion of the combination lock fence lever to ride normally on the outer periphery of the cam wheel so that the fence member associated with the fence lever will not ride upon the tumbler wheels of the lock mechanism. Otherwise, an unauthorized, but lock manipulation skilled person, might endeavor to manipulate the lock mechanism and "feel" the engagement between the fence member and the wheel assembly gates to thereby determine the combination for the lock. However, it has also been found that the engagement between the nose portion of the fence lever and the gate of the cam wheel, by which the fence lever is engaged and operated to move the bolt to an open position by rotation of the cam member, can allow for an unauthorized lock manipulation skilled person to determine where the cam wheel gate is and then by manipulating the lock parts in a predetermined manner also bring the fence member in contact with edges of the gates of the wheel assemblies while the lever nose is positioned in the cam wheel gate.
In order to overcome the contact or "feel" of the fence lever with the rotating lock portions inclusive of the cam wheel and gate wheel assemblies, means have been developed heretofore such as in U.S. Pat. No. 3,991,596, for normally maintaining the fence lever in an inactive position out of engagement with the rotating lock parts. However, it is believed that these prior mechanisms have been fairly complicated in their assembly operations, are not easily added, or adapted to ease of assembly techniques, in mass production of combination locks and generally required some manipulation of the combination of the lock to release the lever in a manner which may or may not be always reliable to cause opening of the lock.